The 2016 campaign is already well underway, and it won’t be long before we’re all inundated with political advertising on the airwaves. Here’s what you need to know about political ads and the (lack of) disclosure around them.

1. Political ads are one of the only ways to trace dark money. While these “social welfare” committees, often 501(c)(4) groups in particular, don’t have to register with the FEC, they do leave a paper trail at local TV stations. FCC regulations require buyers of political ads to identify an officer of their group to the television station and require the local TV stations to make that document, along with other details of the ad purchase, available for public inspection. You can’t always see who’s really paying for the ad, but you can track the spending.

Television and radio stations are required to keep information on the political advertising they sell, and have to make these political files available to the public. Until recently, only broadcast TV stations were required to post this information on the Internet, but a recent FCC ruling mandated that cable, satellite and radio stations also needed upload their political files online. These political files contain valuable information about the ads, such as how much they cost and when they ran, so this was a major victory for transparency.

Online issue ads have the least sunlight. No agency regulates political advertisements on the Internet with any real scrutiny, and disclosure around them severely lacks transparency. Therefore, there are essentially no requirements to report spending or methods to track directly who’s behind an ad, resulting in what we call an “Internet blind spot.” However, you may find line item expenditures listed in FEC reports — but you will find very little information about the substance of that ad.

Political advertisers are required to disclose information about who’s paying for the ads, including the chief executive officers or members of the executive committee or board of directors. Candidates must provide the name of the treasurer of their authorized committees. This information should be enclosed in the political file, but it’s up to the broadcasters and advertisers to hold themselves accountable, and there is little appetite for enforcement from the FCC. What we’re seeing now are groups with benign sounding names like “Americans for an American America,” with no disclosure of the true sponsor (that is, the person or persons backing the group). To combat this lackadaisical oversight, Sunlight and its allies at The Campaign Legal Center and Common Cause are formally urging the FCC to enforce these mandatory disclosure laws. Additionally, we filed a complaint against stations that failed to disclose the true sponsor of political ads that aired.

The IRS has oversight of 501(c)(4) nonprofit social welfare groups, but the FCC oversees political advertising and enforcement of broadcast disclosure rules. If a politically active nonprofit runs ads, the only place they’re required to disclose the information is at the FCC.

If a super PAC makes an ad buy supporting or opposing a particular candidate, it’s considered an independent expenditure, and must also be reported to the FEC. You can follow them in real time, and set up alerts with Sunlight’s Real-Time Federal Campaign Finance tracker here.